﻿using System;
using System.Collections.Generic;
using System.Linq;
using System.IO;
using System.Security.Cryptography;
using System.Text;

namespace LIMS.Common
{
    /// <summary>
    /// 加解密封公共类  用法eg: 
    /// <code>
    ///   Console.WriteLine("-----------DES加密---------------");Console.WriteLine(EncryptHelper.DESEncrypt("tyl_.13795731409", @"id_+>.\("));
    ///   Console.WriteLine("-----------DES解密---------------");  Console.WriteLine(EncryptHelper.DESDecrypt("xg40niWG9BFxPjhFzuaR0ChQA4/fundi", @"id_+>.\("));
    /// </code>
    /// </summary>
    public class EncryptHelper
    {
        #region  DES 加密
        /// <summary>
        /// DES 加密(数据加密标准，速度较快，适用于加密大量数据的场合)
        /// </summary>
        /// <param name="EncryptString">待加密的密文</param>
        /// <param name="EncryptKey">加密的密钥</param>
        /// <returns>加密后的生成的密文字符串</returns>
        public static string DESEncrypt(string EncryptString, string EncryptKey)
        {
            if (string.IsNullOrEmpty(EncryptString) || string.IsNullOrEmpty(EncryptKey))
            {
                throw (new Exception("密文、密匙均不得为空"));
            }
            if (EncryptKey.Length != 8)
            {
                throw (new Exception("密钥必须为8位"));
            }
            byte[] m_btIV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            string m_strEncrypt = "";
            DESCryptoServiceProvider m_DESProvider = new DESCryptoServiceProvider();
            try
            {
                byte[] m_btEncryptString = Encoding.Default.GetBytes(EncryptString);
                using (MemoryStream m_stream = new MemoryStream())
                {
                    using (CryptoStream m_cstream = new CryptoStream(m_stream, m_DESProvider.CreateEncryptor(Encoding.Default.GetBytes(EncryptKey), m_btIV), CryptoStreamMode.Write))
                    {
                        m_cstream.Write(m_btEncryptString, 0, m_btEncryptString.Length);
                        m_cstream.FlushFinalBlock();
                        m_strEncrypt = Convert.ToBase64String(m_stream.ToArray());
                    }
                }
            }
            catch (IOException ex)
            {
                throw ex;
            }
            catch (CryptographicException ex)
            {
                throw ex;
            }
            catch (ArgumentException ex)
            {
                throw ex;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                m_DESProvider.Clear();
            }

            return m_strEncrypt;
        }
        #endregion

        #region  DES 解密
        /// <summary>
        /// DES 解密(数据加密标准，速度较快，适用于加密大量数据的场合)
        /// </summary>
        /// <param name="DecryptString">待解密的密文</param>
        /// <param name="DecryptKey">解密的密钥</param>
        /// <returns>解密后的明文字符串</returns>
        public static string DESDecrypt(string DecryptString, string DecryptKey)
        {
            if (string.IsNullOrEmpty(DecryptString) || string.IsNullOrEmpty(DecryptKey))
            {
                throw (new Exception("密文、密匙均不得为空"));
            }
            if (DecryptKey.Length != 8)
            {
                throw (new Exception("密钥必须为8位"));
            }
            byte[] m_btIV = { 0x12, 0x34, 0x56, 0x78, 0x90, 0xAB, 0xCD, 0xEF };
            string m_strDecrypt = "";
            DESCryptoServiceProvider m_DESProvider = new DESCryptoServiceProvider();
            try
            {
                byte[] m_btDecryptString = Convert.FromBase64String(DecryptString);
                using (MemoryStream m_stream = new MemoryStream())
                {
                    using (CryptoStream m_cstream = new CryptoStream(m_stream, m_DESProvider.CreateDecryptor(Encoding.Default.GetBytes(DecryptKey), m_btIV), CryptoStreamMode.Write))
                    {
                        m_cstream.Write(m_btDecryptString, 0, m_btDecryptString.Length);
                        m_cstream.FlushFinalBlock();
                        m_strDecrypt = Encoding.Default.GetString(m_stream.ToArray());
                    }
                }
            }
            catch (IOException ex)
            {
                throw ex;
            }
            catch (CryptographicException ex)
            {
                throw ex;
            }
            catch (ArgumentException ex)
            {
                throw ex;
            }
            catch (Exception ex)
            {
                throw ex;
            }
            finally
            {
                m_DESProvider.Clear();
            }

            return m_strDecrypt;
        }
        #endregion

    }
}
